The conventional two-stage light emitting diode (LED) driver and one-stage light emitting diode (LED) driver both include electrolytic capacitors having large capacitance to act as an energy storage element so as to provide stable output power. The larger the capacitance employed, the smaller the low frequency (120 Hz) ripple components of the output voltage (current) are, and vise versa. If electrolytic capacitors having large capacitance are not used, then the output voltage (current) fluctuates, which results in a blinking light phenomenon.
Thus, how to avoid the drawbacks of causing fluctuation of the output voltage (current) and the resulting blinking light phenomenon when electrolytic capacitors with large capacitance are not used is worthy of further research and improvement.
Keeping the drawbacks of the prior art in mind, and through the use of robust and persistent experiments and research, the applicant has finally conceived of an electrolytic capacitor-less AC/DC converter and a controlling method thereof.